. >> ifill: now, a second look at a science story that captured headlines this year. the federal government has taken new steps to limit some of the research it does with chimpanzees, which have long been the source of hope and debate. but questions remain about whether those experiments should occur under any circumstances. "newshour" science correspondent miles o'brien reports. >> reporter: there are no other animals quite like them, except us. they share 99% of our d.n.a. and it shows. they scheme, plot and fight. they care for their babies and they grieve their dead. and they love a good game of catch. as i discovered, queenie had little patience for my wild pitches. >> did you see her stomp her foot? >> reporter: she's very mad at me. those very similarities are at the core of a heated debate over whether scientists should keep using chimpanzees for scientific and medical research. do we owe our cousins something more? here, they say we do. welcome to chimp haven, near shreveport louisiana, a 200-acre oasis of tall trees and hidden daily treats for about 130 chim